DE 32 47 603 A1 discloses a carburetor which has a rotatable control drum. The quantity of fuel supplied is controlled via a needle which projects into a fuel opening. In order to adapt the quantity of fuel supplied during idle, an opening is provided in a wall of the control drum, the opening being configured in such a manner that a larger air opening arises on the upstream side of the control drum than on the downstream side.
During the starting, an increased quantity of fuel has to be supplied via the carburetor. For this purpose, it is known to raise the control drum via an actuating mechanism in such a manner that the free cross section of the fuel opening is increased, and at the same time to rotate the control drum in order to increase the opening cross section of the intake channel.
It is also known from WO 2007/077971 A1 to provide, for the starting operation, an additional fuel path which is controlled by an electromagnetic valve. The free cross section of the main fuel opening is controlled by a needle.